Born 26 June, 1902, in Bangor, the elder of the two sons of Morgan Daniel (1864 - 1941), Independent minister, and Anna, his wife. J.E. Daniel was educated at Friars School, Bangor and nurtured in the classical tradition. In 1919 he won a scholarship to Jesus College, Oxford, and in 1922 he took a first class in Classical Moderations and the following year, a first class in Literae Humaniores, followed by a first class in divinity in 1925. In the same year, a ‘fellowship’ was created for him at Bala-Bangor College and on the death of Dr. Thomas Rees, he was appointed a full professor on 28 July, 1926, to be responsible for the courses on Christian doctrine and the philosophy of religion. In 1931 he was freed from his work to study with Rudolph Bultmann in Marburg. He remained at Bala- Bangor until January 1946 when he was appointed a Ministry of Education inspector of schools with special responsibility for religious education and the classics. During this time, he lived first of all at Wick, Glamorgan and subsequently at Tŷ Gwyn, Botffari, Flint. He was killed in a road accident near Halkyn in Flintshire on 11 February 1962 and his remains were interred in the New Cemetery at Bangor. He married Catrin, daughter of Rowland Hughes (1870 - 1928), an Independent minister, and they had five children.

Possessing outstanding academic qualifications, Daniel was one of the most able theologians of his generation, combining wide knowledge, an unfailing memory and a superb analytical mind. He was strongly influenced by the teachings of Karl Barth and Rudolph Bultmann in the stirring days of their early efforts. He shared their challenging spirit and their keen criticism of current theological thinking, creating thereby fierce opposition. However, Daniel was the most able interpreter of the reaction against the liberal theology movement in Wales. Despite this, his literary contribution to this field was sparse. He published Dysgeidiaeth yr Apostol Paul (1933) and a handful of articles in various journals. He was not ordained but there was great demand for his services as a preacher because of the stirring power of his sermons which combined a broad culture with fiery conviction.

He was a staunch nationalist. He came to early prominence as one of the leaders of Plaid Genedlaethol Cymru which was established in 1925. He was a regular contributor to its newspaper, Y Ddraig Goch, and he stood as a candidate in four general elections. He was a vice-chairman of the party from 1931 to 1935 and he followed Saunders Lewis as its chairman in 1939 and held the office until August 1943.

Daniel was notable for his broad culture, his exceptionally brilliant mind and the strength and richness of his grasp of the Welsh language, both orally and in writing, his zeal for everything that was good in Wales and for the Christian faith above all else.